/**
 * Created with IntelliJ IDEA
 * Description:
 * User: Administrator
 * Data: 2023 - 07 - 05
 * Time: 16:12
 */
import java.util.*;
class Solution5 {
    public int romanToInt(String s) {
        int preNum = getVal(s.charAt(0));
        int num = 0;
        int sum = 0;
        for(int i = 1; i < s.length(); i++) {
            num = getVal(s.charAt(i));
            if(preNum < num) {
                sum -= preNum;
            }else {
                sum += preNum;
            }
            preNum = num;
        }
        sum += preNum;
        return sum;
    }
    private int getVal(char c) {
        switch(c) {
            case 'I':
                return 1;
            case 'V':
                return 5;
            case 'X':
                return 10;
            case 'L':
                return 50;
            case 'C':
                return 100;
            case 'D':
                return 500;
            case 'M':
                return 1000;
        }
        return 0;
    }
}
